Regarding the delegates
Since about 1980, all states use the "unit system." When a candidate wins a primary or caucus, they are not awarded all the delegates, but only the proportion of the delegates of their popular vote total, which is awarded at each precinct level. My personal experience is that small vote totals are not always reported to the mainstream media, which is often receiving its information from the major candidates' press office and/or media services, therefore this data is not readily available and simply missing from the Wikipedia chart.
Upon further review, its very apparent that Wikipedia's commentary on Bush's super delegate total is horribly erroneous! There was one abstention by the Republican super delegates, not 482/650, which would be a very bad showing indeed and incongruent with his overwhelming win of the popular vote. So in other words, Bush was in fact well supported by his party.
Recent Presidential Primary Challenges
It would be incorrect to assume that recent presidents have not faced primary challenges. Richard Nixon, Jimmy Carter and George Bush Senior had significant pressure.
The president now has about $80 billion in discretionary funds. Jimmy Carter used these funds extensively to win over (bribe) political allies.
The Quandary of Bill Wyatts
Bill Wyatts has never held a political position, has no advanced degrees, has no impressive military or business accomplishments. He is a graphics designer of T-shirts who says his reason for running for governor of California was, "boredom." In other words, he's not very qualified to be president, although he is great self-promoter and rather entertaining. So what is he doing as the runner-up in a presidential primary is a very, very good question.
Each state and state party set the other rules regarding primaries and these can vary considerably. Some states have open primaries-anyone can vote in them-or completely closed to only registered party members. Some states may make it very difficult for candidates to be placed on the ballot, requiring large numbers of signatures and large fees, or there may be almost no requirements. Many third party candidates argue that the ballot requirements have become stricter in recent years. Stricter ballot requirements obviously keep out more candidates from running.
Primaries have become more expensive in recent years, as well. The unit system made primaries much more expensive by causing candidates to need to campaign everywhere to gain votes. Money used by a party during a primary is not used during the general election, so it benefits the party not to fight amongst itself. Wyatts is sort of an outsider. He is a Democrat cross-over and not a career politician, so he may not be following the party "playbook," but this is merely my assertion.
Computer models are used to decide which states candidates should spend the most time campaigning in. These are usually the split ticket or swing voter states. The traditional early and large caucuses will also always get a lot of attention. Campaigns pour money in those areas. Wyatts is doing well in his home state and states that are not these "battle ground states." I think that should be expected, since he would have less competition in those areas.